I can't access Custom Form Styles"We're sorry, we can't find the page you requested"Followed guidance from community but didn't workCan you help on this issue ?

Thanks for bringing this up in the Community, operations-bestb. Let me guide you further so you can access Custom form styles.

I appreciate your time taking some troubleshooting steps. Since you're still getting the same error, I suggest contacting our technical support team. They have the necessary tools to review your account and identify the root cause of this issue. They can also suggest ways to fix the problem. 

Here are the steps to reach our live support team:

1. Go to the Help menu.
2. Proceed to the Assistant tab.
3. On the chat box, type in a keyword and hit Enter.
4. Select QuickBooks Online Support, then click Contact us.
5. Click Ask about something else, then enter your concern.
6. Choose  Chat.

Moreover, you can check out their hours of availability.

For more organized recordkeeping, kindly access this article: Adding or deleting attachments in QBO.

Feel free to comment below If you have further questions about customizing your forms. We're always here to assist you.